It might have; software engineering is a big tent, and people who touch Github (in at least someway) no doubt comprise a huge part of it. Full disclaimer, I'm biased, as I opened an issue attempting to address some potential editorial/tone issues, and the initial response was not good (a big part of that may be questions of who exactly is "involved" with the letter. How should others become involved and contribute in a way the OPs feel is constructive?)
As another commenter pointed out, not everything is so black and white. In this case, no one should be "beyond reproach", but what seem like simple issues to Issues may indeed be representative of strong product/technical decisions from an opinionated vendor. IMO it's not inherently clear that the people behind dear-github entirely recognized the nuance here. No one is looking to pick fights or troll anyone, because no, not everyone who is passionate about this issue is a meanie. That said, the original letter and the immediate response could be interpreted as brash, and to that end, I wouldn't be surprised that someone responded with thank-you-github as an opposite reaction.